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FAX Redirection Topology

Wei Yang

7/16/12

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Redirector hardware at CERN

• Redundant redirectors for EU, UK, DE, FR– Redundant (the “+” sign below) VMs– More to come

• atlas-xrd-eu.cern.ch+– xrootd port 1094, cmsd port 1098– SLAC test machine can join it, working as expected

• atlas-xrd-uk.cern.ch+– Report to EU redirector– Xrootd port 1094, cmsd port ?– SLAC can’t join it, debugging …– Same for DE and FR redirectors

7/16/12

3

Redirector topologyEU rdr

DE rdr UK rdr US rdr

US rdr

Glasgow rdr Middle West rdr

Site 1 rdr Site 2 rdr Site A rdr Site B rdr

cmsd & xrootdredirection

Mature xrootdredirection

• cmsd based redirection search the branch under it• xrootd based redirection is used to jump to upper level

if cmsd search return nothing• US can either report to EU redirector, or as a peer of EU

depend on needs, latency, or performance7/16/12

Steal from Andrew Hanushevsky 4

# CMSD redirection:

all.role managerall.manager leftregion:1234

# Upper level redirectorall.manager meta xyzzy:1234

$ XROOTD redirectionxrootd.redirect xyzzy:1234 ? /

all.role managerall.manager rightregion:1234all.manager meta xyzzy:1234xrootd.redirect xyzzy:1234 ? /

How the topology works

Global Redirector“xyzzy”

Regional Redirector Regional Redirector

Local Redirector

Proxy Server Proxy Manager

Local Redirector

Server Proxy Server Server

all.role meta managerall.manager meta xyzzy:1234

all.role managerall.manager lefthand:1234all.manager meta leftregion:1234xrootd.redirect leftregion:1234 ? /

all.role managerall.manager righthand:1234all.manager meta rightregion:1234xrootd.redirect rightregion:1234 ? /

all.role serverall.manager leftregion:1234ofs.osslib psslib.sopss.origin mycluster:1094

all.role proxy managerall.manager meta leftregion:1234xrootd.redirect xyzzy:1234 ? /

Site DSite A Site B Site C

7/16/12

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Topology verification

Goal: diagnose broken node in the topology• Deploy site specific (small) file with known checksum • Access from global redirector

– Test full redirection chain + N2N• For every lower level redirector

– Test a file not exists in its domain

How to find out that the actual topology is?• Who know how do this manually• We need to do it automatically and produce a graph

7/16/12